Laboratory tests of the pleural effusion indicated leakage fluid with the following results: light yellow turbid liquid, Rivalta test (+), total cells count 152 × 106, monocytes accounting for 90% of total white blood cells, white blood cells count 140 × 106, protein 27.7 g/L, glucose 11.87 mmol/L, lactate dehydrogenase (LDH) 106 U/L, and adenosine deaminase (ADA) 4 U/L. The gene discussed is ADA; the disease is Pleural effusion.